Data Security, Integrity and Ethics: Question 1

Worked solution

Why B is correct

A worm is a standalone piece of malware. Once it is running on one machine, it can scan a network for other vulnerable devices and copy itself onto them directly, without needing to attach itself to another program or file, and without needing a user to open anything for it to spread further. This is what makes worms capable of spreading extremely quickly across a network.

A virus works differently: it attaches its code to a legitimate host program or file (such as a document or an executable). It only runs, and only spreads to further hosts, when that infected host program or file is opened or run. Usually because a user has been tricked into doing so. Without a host file and some user action to trigger it, a virus cannot spread.

Option B states this correctly: a worm self-replicates across a network with no host file and no user action needed, while a virus needs both a host file and a user action to spread.

Why the other options are wrong

• A swaps the two definitions around: it is the worm that needs no host file and no user action, not the virus.
• C is wrong on two counts: the terms are not interchangeable, and it is not true that both types always need a host program and user action. A worm specifically does not.
• D mixes up the malware types. Disguising itself as legitimate software to trick a user into installing it is characteristic of a trojan, not a worm; and spreading automatically across a network without any host file is characteristic of a worm, not a virus. So D has effectively swapped virus and worm’s properties while also borrowing a trojan’s disguise behaviour.

Final answer

B, a worm self-replicates and spreads across a network independently, with no host file or user action required; a virus attaches to a host file and typically needs a user action to spread.